UV LED Reduces Epileptic Seizures

Researchers from the University of Minnesota Medical School, led by Steven Rothman MD, placed a microelectrode in the brains of rats, which were sent constant pulses of UV light. During the study, UV light released gamma aminobutyric acid (GABA) from the "caged" compound carbonyl amino butanoic acid (BC204). GABA then decreased the abnormal electrical activity in the CA1 area of the brain. The researchers found that the method discharged a population of neurons in the rats, which had had seizurelike activity induced.

Illumination of control slices with up to 200-mA LED current had no effect on peak amplitudes; however, the addition of BC204 (30 µM) and illumination using as little as 50-mA LED current produced a statistically significant reduction of the peak of the population spike. More important, BC204 (10 µM) significantly reduced the slice spikes and bursting induced by the 4-AP and low magnesium.

Researchers believe that a programmable pump could deliver the caged GABA into the subarachnoid space over the epileptic area of the brain. By using techniques similar to those used for cortical stimulation units that are currently in clinical trials, UV LEDs could be responsively activated to release GABA.

"Our strongly positive results, in an epilepsy model far more severe than the naturally occurring disease, suggest that this technique could translate to human epilepsy," said Dr. Rothman. Focal (or partial) epilepsy is very common in both adults and can occur in children. It is caused by an abnormality in a localized area of the brain resulting from such conditions as stroke, trauma or infections. Up to one-third of epileptic patients fail to respond to conventional medical therapies and are subject to toxic effects from antiepileptic drugs (AEDs). While surgery has benefited some patients with focal epilepsy, a substantial number of patients do not experience a complete remission after operation, prompting researchers to investigate alternative treatments.

The researchers are optimistic that an LED-based implantable device is feasible.

"Optical stimulation would be a far more rapid delivery method than any mechanical device for direct administration of drug into the brain and would not subject patients to toxic doses of medication or irreversible brain damage from epilepsy resections," concluded Dr. Rothman.

Details of this study are available in the January 2010 issue of Epilepsia, a journal published by Wiley-Blackwell on behalf of the International League Against Epilepsy.